Terminal cover



March 1, 1966 c. A. BOSCH ETAL 3,238,291

TERMINAL COVER Filed April 5, 1965 2 Sheets-Sheet 1 I4 1 l I 2 l l I4 I09 43 2| 3 g 45 18 1| I '7 i =1 8 r 4 I9 I 6 H I0 2 E? :3 I I I 4 I L g24 I 224 L In] C 1 I I FIG. 2 l I L I I lNVENTORS m 11]] JAMES I.METZGER JR.

' CLARENCE A. BOSCH FIG "1 WQM TERMINAL COVER Filed April 5, 1965 2Sheets-Sheet 2 35 I INVENTORS u JAMES l- METZGER JR- 47 47 47 CLARENCEA- BOSCH United States Patent 3,238,291 TERMINAL COVER Clarence A.Bosch, Ferguson, and James I. Metzger, Jr., St. Louis County, Mo.,assignors to Wagner Electric Corporation, St. Louis, Mo., a corporationof Delaware Filed Apr. 5, 1965, Ser. No. 445,418 4 Claims. (Cl. 174-138)This invention relates to bushings mounted on electrical apparatus andmost particularly to a cover for the terminal assembly end of thebushing.

It is well known in the electrical industry that a short circuit may beformed in an electrical apparatus, such as a distribution transformer,by animals simultaneously contacting the lid of the transformer and theterminal assembly connected to the bushing. It has been found desirablein an attempt to minimize the possibility of animals causing these shortcircuits to provide an electrical non-conductive cover on the terminalassembly end of the bushing. Some of these prior art terminal covershave used additional members assembled to the main body of the terminalcover to insure proper location and secure fit over the terminalassembly thereby requiring ,assemblance of the terminal cover before itcan be placed over the terminal assembly. Other prior art terminalcovers lack locking or form-fitting features so that the terminal covercan turn about the terminal assembly resulting in the misalignment ofthe arrestor gap hole with respect to the arrestor spark gap formedbetween the terminal assembly and the lightning arrestor. Still other ofthese prior art terminal covers have been secured to the terminalassembly end of the bushing by snapping over the top petticoat which hasthe undesirable feature of diminishing the creep and flashover distancesof the bushing and of requiring a large configuration terminal covertofit over the top petticoat. Also, some of the terminal covers are tapedonto the bushing to prevent dislocation and rotation of the terminalcover relative to the terminal assembly thereby establishing theundesirable feature of making it possible for water to be trapped withinthe area above the top petticoat.

It is therefore a general object of this invention to provide .a novelterminal cover which substantially encloses the terminal assembly andwhich overcomes the aforementioned disadvantages.

Another object is to provide a one piece terminal cover which iseconomically manufactured and is simply assembled to the terminal end ofthe bushing. 1

Another object is to provide a terminal cover which locks onto theterminal assembly by snapping over the bottom flange of the terminalassembly.

A further object is to provide a one piece terminal cover having apre-formed shape approximately the shape of the terminal assembly whichprovides maximum enclosure of the terminal assembly.

A further object is to provide a terminal cover which completelyencloses the terminal assembly except for the lightning arrestor gaphole and which, due to the formfitting feature of the terminal cover,insures proper positioning and prevents dislocation thereby providingfor the proper alignment of the arrestor gap hole with'respect to theterminal assembly.

Still another object is to provide a novel terminal cover having anextended conical section severable to form an aperture with a diametercomplementary to the diameter of the power line which passes through theterminal cover 1 to be connected with the terminal assembly.

Still another object is to provide an improved terminal cover havingmeans for draining water therefrom which may enter the terminal cover.

These and other objects and advantages will become apparent hereinafter.

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Briefly, in accordance with one aspect of the present invention, aterminal cover for substantially enclosing an electrical terminal isprovided with lip means for grip ping engagement with the terminal forremovably securing the cover to the terminal. In accordance with anotheraspect of the invention, a terminal cover for substantially enclosing anelectrical terminal having an electrode for a spark gap is provided withaperture means for the spark gap and abutment means engageable with aportion of the terminal to predeterminately maintain alignment betweenthe aperture and electrode.

In the drawings which illustrate an embodiment of the invention,

FIG. 1 is a sectional view of a terminal cover in accordance with thepresent invention positioned over a terminal assembly,

FIG. 2 is another sectional view of the terminal cover taken along theline 2-2 of FIG. 1,

FIG. 3 is a sectional view of the terminal cover of FIG. 1 but in itsmanufactured state,

FIG. 4 is another sectional view of the terminal cover taken along theline 44 of FIG. 3, and

FIG. 5 is another sectional view of the terminal cover taken along theline 55 of FIG. 4. 1

Referring now to FIGS. 1 and 2, a conventional bushing 1 is mounted onthe cover of an electrical device, such as a distribution transformer(not shown), and a terminal assembly of standard construction, indicatedgenerally at 2, is provided with a cast body portion 3 having an annularflange mounting base 4 which is threadedly received and abuttinglyengages the top of said bushing. An arm portion 5 integrally connectedto the cast body portion 3 acts as an electrode for a spark gap from alightning arrestor (not shown), and an aperture 6 provided through saidcast body portion has an axis 7 perpendicular to said arm portion. Aneye bolt member 8 includes a threaded portion 9 extending through theaperture 6 having a nut 10 threadedly received thereon, and a springmember 11 is positioned between said nut and the cast body portion 3about said threaded portion. A power line 12 is clamped between the eyebolt member 8 and the cast body portion 3 due to movement of said eyebolt member toward said cast body portion as the nut 10 is rotated onthe extending threaded portion 9 in a direction compressing springmember 11 against said cast body portionc A terminal cover 13 ispositioned over the terminal assembly 2 and at the upper extremity ofsaid terminal cover is provided an aperture 14 through which the powerline 12 passes to be connected with said terminal assembly.

Referring now to FIGS. 3, 4 and 5, the terminal cover 13 consists of anelectrically nonconducting material having a pre-formed shape whichincludes a beveled base portion 15 and a constant diameter main bodyportion 16 having projections 17, 18 and protuberance 19 incorporatedtherein to approximate the configuration of the terminal assembly 2. Anextended conical portion 20 is integrally connected to the main bodyportion 16 at a tapering neck portion 21 and therefrom progressivelydecreases in diameter to a closed tip 22. Calibrated markings may beprovided along the length of the conical portion 20 for indicating theproper point of severance of said conical portion to form the aperture14 with a diameter corresponding to the diameter of the power line 12.The main body portion 16 has an interior diameter 23 which willaccommodate the annular flange mounting base 4 of the terminal assembly2 when the terminal cover 13 encloses said terminal assembly. A lip 24,provided in the interior of the terminal cover 13 at the intersection ofthe body portion 16 and the beveled base portion 15, defines anotherinterior diameter 25 substantially smaller than the interior diameter 23with said lip being yieldable to thereby permit the interior diameter 23to receive the annular flange mounting base 4.

As shown by the embodiments of the present invention in FIGS. 1 and 2,the aperture 14 formed in the conical portion 20 for receiving the powerline 12 is substantially aligned with respect to the terminal assembly2. This alignment may be accomplished, as shown in FIG. 3, by having theconical portion 20 eccentrically positioned with respect to a centralaxis 26 of the main body portion 16 at a circumferentially predeterminedlocation from the projection 17, or depending upon the type of terminalassembly to be enclosed, this alignment may be accomplished by havingsaid conical portion axially aligned with said central axis.

Referring again to FIGS. 3, 4 and 5, the projection 17 is provided inthe periphery of the main body portion 16 for covering the extendedthreaded portion 9 and the nut 10 of the terminal assembly 2. Theexterior of the projection 17 provides an extended oblong portion 27which obliquely rises from the beveled base portion to a predeterminedpoint 28 from the central axis 26 and therefrom acutely recedes untilsaid oblong portion is incorporated in the periphery of the main bodyportion 16. Stepped grooves 29 and 30 are provided in the interior ofthe oblong portion 27 intersecting the beveled base portion 15 andextending to an upper interior wall 31 defined by said oblong portion.The narrower groove 29 is provided to receive the extended threadedportion 9 and follows the oblique configuration of the oblong portion 27so that a bottom 32 of said narrow groove is further away from thecentral axis 26 at the upper interior wall 31 than at the intersectionof said narrow groove with the beveled base portion 15. The broadergroove 30 is centered with respect to the groove 29 and is provided inthe interior of the oblong section 27 for receiving the nut 10 on thethreaded portion 9. A bottom 33 for the broader groove 30 is formed atthe intersection of the stepped grooves 29, 30 with said bottom, fromthe upper interior wall 31 to the intersection of said broader groovewith the beveled base portion 15, maintaining a constant distance 34from the central axis 26.

The protuberance 19 for enclosing the eye bolt member 8 iscircumferentially predeterminately located from the projection 17 and isprovided on the terminal cover 13 to permit a variable amount ofextension of said eye bolt member from the cast body portion 3 in theclamping of a variable diameter power line in the manner hereinabovedescribed and as illustrated in FIG. 2 using the power line 12.

Projection 18 is predeterminately circumferentially located with respectto projection 17, and is incorporated in the periphery of the main bodyportion 16 for enclosing the arm portion 5 of the cast body portion 3.The exterior of projection 18 consists of a rectangular raised portion35 which has one end intersecting the beveled base portion 15 and theother end thereof intersecting a protruded section 36 which extends fromthe periphery of the main body portion 16 to a greater degree than doessaid rectangular raised portion. A groove 37 having a base wall 38 at aconstant distance 39 from the central axis 26 is provided in theinterior of the projection 18 and corresponds to the rectangular raisedportion 35. A recessed cavity 40 is provided in the interior ofprotruded section 36 having a cavity wall 41 at a distance 42 from thecentral axis 26, and said distance 42 is greater than the distance 39 tothe base wall 38 of the groove 37. The groove 37 has one endintersecting the beveled base portion 15 and the other end thereofintersects the cavity 40. An aperture 43 is provided through theterminal cover 13 in the protruded section 36 with said aperture beinglocated at a predetermined distance 44 from the lip 24 and saidpredetermined distance corresponds and is equal to a distance 45 betweenthe bottom of annular flange mounting base 4 and the arm portion 5.Therefore, when the terminal cover 13 is properly positioned over theterminal assembly 2, the arm portion 5 is substantially aligned with theaperture 43.

The interior wall of the main body portion 16 is provided withindentations 46, and the beveled base portion 15 is provided with ribsections 47 which for clarity and understanding were not shown in FIGS.1 and 2 but are hereinafter described. The indentations 46 extendthrough the lip 24 to establish a drain path from the interior of theterminal cover 13 past said lip, when said l=ip is grippingly engagedwith the flange mounting base 4 of the terminal assembly 2, for thedrainage of water which may enter said terminal cover through theapertures 14 and 43. Rib sections 47 are provided on the interior of thebeveled base portion 15 adjacent to the stepped grooves 29, 30 ofprojection 17, the groove 37 of projection 18 and the indentations 46for abutting engagement with the bushing 1 adjacent the terminalassembly 2. The rib sections 47 establish clearance between the bushing1 and the beveled base portion 15 so that water which enters theterminal cover 13 may drain through the groove 37, stepped grooves 29,30 and the indentations 46 and therefrom past said beveled base portiondue to the clearance between said bushing and said beveled base portion.The indentations 46 also allow for extra expansion of the terminal cover'13 when being placed over the terminal assembly 2.

In the use of the terminal cover 13, the extended conical portion 20 issevered to form an aperture 14 having a diameter complementary to thediameter of the power line 12. The power line 12 is then insertedthrough the aperture 14 and the terminal cover 13 is slipped along saidpower line to .a position away from the terminal assembly 2, asillustrated in FIGS. 1 and 2 and with said terminal cover in thisposition, said power line may be connected with said terminal assembly.After the power line 12 is connected with the terminal assembly 2, theterminal cover 13 is positioned so that projection 17 is aligned withthe threaded portion 9 and the bolt 10 which, due to the pre-formedshape of said terminal cover, will predeterminately align projection 18with the arm portion 5 and protuberance 19 with the eye bolt member 8.As the terminal cover 13 is pushed downward over the terminal assembly2, the protuberance .19 accommodates the movement therein of the eyebolt member 8, and the extended threaded portion 9 and the bolt 10 arereceived In the stepped grooves 29, 30 of the projection 17. Also, theprojection 18 provides the groove 37 to accommodate the movementthereth-rough of the arm portion 5 to a position in the recessed cavity40 so that said arm portion will be so aligned with respect to theaperture 43 provided in the protruded section 36 that said terminalcover will not interfere with the spark gap esta lished between said armportion and the lightning arrestor previously mentioned. The lip 24 thenyields topermit the annular flange mounting base 4 to be received in theinternal diameter 23 of the main body portion 16, and said lip thensnaps over said annular flange mounting base to engageably secure theterminal cover 13 in place. The terminal cover 13 is prevented fromrotating on the terminal assembly 2 due to the form-fitting feature ofsaid terminal cover so that the arrestor gap hole, aperture 43 will notbe misaligned with respect to the arm portion 5 and the lightningarrestor spark gap will thereby be maintained. Also, the indentations 46and the rib sections 47 will provide a means of escape past the lip 24for water which may enter the terminal cover 13 through the apertures 14and 43.

From the foregoing, it is now apparent that a novel terminal cover isprovided meeting the objects set out hereinbe fore and that changes inthe shape or configuration may be made by those skilled in the artwithout departing from the spirit of the invention, as defined by theclaims which follow.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In combination with a terminal connecting a power line with anelectrical bushing and having extended portions including a radiallyoutwardly extending arm portion serving as an electrode for a lightningarrestor spark gap, a cover of insulating material substantially whollyenclosing said terminal and having an inner side wall portion in a planespaced radially outwardly from the radially outer end of said armportion, aperture means in said side wall port-ion providing limitedaccess through said cover to said arm portion end preventing said coverfrom interfering with said spark gap, internal groove means in saidcover receiving one of said extended portions and having opposedsurfaces engageable with opposed sides of said one extended portiontosubstantially prevent rotation of said cover relative to said terminaland predeterminately maintain alignment between siad aperture means andsaid arm portion end, and other aperture means in said cover receivingsaid power line.

2. In combination with a terminal mounted on an electrical bushingincluding clamping means for connecting a power line to said terminaland a radially outwardly extending arm portion serving as an electrodefor a lightning arrestor spark gap, a cover of insulating materialhaving an inner Wall substantially wholly enclosing said terminal andhaving an inner side wall portion in a plane spaced radially outwardlyfrom the radially outer end of said arm portion, an internal groove insaid inner wall for receiving said clamping means, said groove havingopposed side portions engageable with opposed sides of said clamp-ingmeans to substantially prevent rotation of said cover relative to saidterminal, aperture means in said side wall portion providing limitedaccess theret-hrough predeterminately aligned with said end of said armportion to prevent said cover from interfering with said lightningarrestor spark gap, and other aperture means in said cover for receivingsaid power line.

3. In combination with a terminal mounted on an electrical bushing forconnection with a power line and having extended portions including aradially outwardly extending arm portion serving as an electrode for alightning arrestor spark gap, a cover of resilient insulating materialhaving an inner wall substantially wholly enclosing said terminal, agroove in said inner wail for receiving said arm portion, said groovehaving opposed side portions engageable with opposed sides of said armportion to substantially prevent rotation of said cover relative to saidterminal, said groove having a bottom wall portion in a plane radiallyoutwardly of and facing the radially outer end of said arm portion,first aperture means in said bottom wall portion providing limitedaccess through said cover to said arm portion end and predeterminatelyaligned therewith to prevent said cover from interfering with saidlightning arrestor spark gap, and second aperture means in said coverfor receiving said power line.

4. In combination, a terminal having a body portion with mounting flangemeans thereon engaging an electrical bushing, a radially outwardlyextending arm portion provided on said body portion serving as anelectrode for a lightning arrestor spark gap, clamping means provided onsaid body for connecting a power line to said terminal, a non-conductiveyieldable cover having an inner wall substantially wholly enclosing saidterminal lip means on said cover for gripping engagement with saidmounting flange means to secure said cover in enclosing relation withsaid terminal, first projection means on said cover defining a firstinternal groove for receiving said clamping means, second projectionmeans on said cover defining a second internal groove for receiving saidarm portion, said first and second grooves having opposed sidesrespectively engageable with opposed sides of said clamping means andsaid arm portion to substantially prevent rotation of said coverrelative to said terminal, said second groove also having a bottom Wallin a plane radially outwardly of and facing the radially outer end ofsaid arm portion, first aperture means in said bottom wall providinglimited access through said cover and predeterminately aligned with saidarm portion end to prevent said cover from interfering with saidlightning arrestor spark gap, and second aperture means in said coverfor receiving said power line.

References Cited by the Examiner UNITED STATES PATENTS 2,065,315 12/1936Keath 1745 X 2,263,319 11/1941 Treanor 1745 X 2,715,654 8/1955 Lucas174-77 2,834,829 5/1958 Broverman 174-138 2,875,267 2/1959 Sutton 1741383,019,287- 1/1962 Newcomb et a1 l745 X 3,145,421 8/ 1964 Colbert.

LARAMIE E. ASKIN, Primary Examin r.

1. IN COMBINATION WITH A TERMINAL CONNECTING A POWER LINE WITH ANELECTRICAL BUSHING AND HAVING EXTENDED PORTIONS INCLUDING A RADIALLYOUTWARDLY EXTENDING ARM PORTION SERVING AS AN ELECTRODE FOR A LIGHTNINGARRESTOR SPARK GAP, A COVER OF INSULATING MATERIAL SUBSTANTIALLY WHOLLYENCLOSING SAID TERMINAL AND HAVING AN INNER SIDE WALL PORTION IN A PLANESPACED RADIALLY OUTWARDLY FROM THE RADIALLY OUTER END OF SAID ARMPORTION, APERTURE MEANS IN SAID SIDE WALL PORTION PROVIDING LIMITEDACCESS THROUGH SAID COVER TO SAID ARM PORTION END PREVENTING SAID COVERFROM INTERFERING WITH SAID SPARK GAP, INTERNAL GROOVE MEANS IN SAIDCOVER RECEIVING ONE OF SAID EXTENDED PORTIONS AND HAVING OPPOSEDSURFACES ENGAGEABLE WITH OPPOSED SIDES OF SAID ONE EXTENDED PORTION TOSUBSTAN-